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Explore Scientific 16" dob


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Ah sorry just reread and it arrived 'yesterday' apologies for mentioning clear skies on Tuesday :)

:laugh:

Looking good.

How did you find the different focuser vs finder new positioning?

Also, another thing I noticed with these scopes is the fine tuning  knob is on top....is it as easy to reach?

I haven't tried it properly yet, but I see nothing inherently wrong with it being on the right, other than I'm not used to it. We'll have to see how it is once I've done the shroud. It also helps that the Telrad is on a riser.

Fine-tuning knob not a problem: I usually move dobs by grabbing the top of the secondary cage anyway.

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I like the idea of collimating the primary from the eyepiece. How does that work? Really long arms?

In the "through-the-focuser" shot above, you will see a bolt-head just outside the primary at the 5 o'clock position, and part of one at the 1 o'clock position. These are two of the three collimating bolts.  They have a socket for a 6mm hex wrench (Allen key). The scope is supplied with a 3-ft rod that has a tee-piece at the hand end and a 6mm hex, protected by a small plastic cup (that prevents you accidentally touching the primary with the metal), at the business end.

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Now the shroud: definitely a a prototype; just made with stuff from the kite-making box, and I didn't have enough shock-cord, so it's pulling a bit tight. left open at the bottom to improve the efficiency of the boundary layer fans. Need to get some kyvek to fill in the top gap in  the secondary cage, or the secondary is bound to dew up.

post-358-0-85448000-1396546234_thumb.jpg

Also discovered today that, with tip positive, the fans suck. That was after I'd made a 2.1 > 2.5 adaptor, which I could have wired tip negative had I known.... Re-soldering tomorrow. Pub quiz tonight (which is just as well, 'cos it's cloudy and I want to get this beastie (for which I must find a name) under the stars...)

Oh, and mounting the telrad base like I did in the earlier pics, limits the ways I can orientate the secondary cage when I pack it away in the rocker box.

Tomorrow (or soon thereafter): pole bag and secondary cover.

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Does anyone else have a problem with that page loading ? How much data is on/in it ?

Everytime I go there my poor ol little laptop/firefox gets confusled for about 10mins before I can regain control of things :(

Anyone got a plain text version of the content please ! ?

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Does anyone else have a problem with that page loading ? How much data is on/in it ?

Everytime I go there my poor ol little laptop/firefox gets confusled for about 10mins before I can regain control of things :(

Anyone got a plain text version of the content please ! ?

Further to my PM (for others: I suggested telling FF not to load images - easiest way is probably  about:config > permissions.default.image >2 --- change it back to 1 when you want images to reload), you can also Ctrl-U to see the source, and read the page text there. Alternatively, if you have AdBlock (and you really should, along with NoScript), you can  tell it to block certain images.

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Further to my PM (for others: I suggested telling FF not to load images - easiest way is probably  about:config > permissions.default.image >2 --- change it back to 1 when you want images to reload), you can also Ctrl-U to see the source, and read the page text there. Alternatively, if you have AdBlock (and you really should, along with NoScript), you can  tell it to block certain images.

Excellent ! Thanks, instant cure !

My HD and Swapfile will be eternally grateful to you :)

Yes, I have AdBlock (another good tip from Steve for anyone who does not yet have it), dont remember anything about images in there though, will have another look in a min.

Not heard about NoScript, will check it out, thanks, cos I do get 'script in page errors' time to time.

All we need now is a temptation resist app :) :)

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Further improvements:

* Modded the shroud a bit, including adding velcro so it can be used with the supplied light shield.

* Added colour-coded hair elastics to the trusses, so that I can put them in the same place every time and also holds the ends together when I'm setting up, to avoid the "wrestling an octopus" syndrome.

* Made a bag for the truss poles and collimation tube.

Failed to sort out the fans. I made an adaptor to provide 12V tip negative: nada. Investigation with a multimeter indicates that there is reverse polarity protection somewhere in the circuitry in the mirror box.

Brief First Light

It was predicted to be reasonably clear last evening so, just before sunset, I packed it into my small hatchback (seats down, of course) and took it up to Hyde Common.  Observing spot is around 50m from the car park. It took almost exactly 30 minutes to take it from the car and set it up. I really appreciate that collimation tool (a friend was collimating a 300P and getting mine done was much , much quicker)! Still, this takes 20 minutes longer than setting up the big binos/P-mount.

As it was still very light, first target was the Moon. With a CC and 24mm ES N2, the lunar surface was crisp and showed wonderful detail. My Orthos couldn't come to focus with the CC, so had to be used without it. The fans did make a difference, even though they suck.

Lots of detail on an almost too bright Jupiter at x150-ish; tried x360-ish, but the atmosphere couldn't take it (not good seeing). GRS very obvious.

Dew was becoming a problem and, by  the time the Coma galaxies were at a decent altitude, my Telrad had dewed up (it's dew shield had gone AWOL from the case), so I was effectively stymied. Shroud became dripping wet, but secondary remained undewed.

Owing to the poor seeing, I was unable to star-test the optics but, to say that I am pleased with what I have seen of/through it so far, I am very pleased.

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How was dew affecting the primary?

Not at all, with the shroud. However, the Telrad was doing it's prime (but unadvertised) task of being the most sensitive dew detector since the Big Bang!

On the batphone, so expect weird autocorrect

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16'' portable...after the ES 12'' this is going to be a bit of a game changer.

Will be looking for the various reports, but both diameters sound like they have great potential.

How do you get on with the veiwing point being on the left of the OTA anf effectively using the finder with the left eye..or is there enough room to view right eyed?

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Not at all, with the shroud. However, the Telrad was doing it's prime (but unadvertised) task of being the most sensitive dew detector since the Big Bang!

On the batphone, so expect weird autocorrect

That's not bad at all. I'm now torn between the ES 16" and the SW 14" for my next plunge a couple of months from now. Out of curiosity, can you lift the entire fully assembled set-up, say, 5 meters distance? Are the poles solidly connected to the top and bottom that you can lift the whole lot without anything snapping apart :) ?

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How do you get on with the veiwing point being on the left of the OTA anf effectively using the finder with the left eye..or is there enough room to view right eyed?

It's a non-issue for me: the Telrad is on a riser, so I can use either eye, but I use reflex finders (and straight finderscopes) with both eyes open anyway. I found that, after a while, I was using my left eye on the Telrad, simply because it was less far to bend (my back doesn't like bending!) The finderscope is a right-angle one anyway, so it doesn't matter what side it is on.

I did have a good look at the secondary cage and it would be simple enough to mod it, but I don't think I'll bother. Within a very short time (i.e. 10 minutes), sitting on the "wrong" side seemed natural and one advantage to the eyepiece always being horizontal is that my floaters aren't exacerbated by looking downwards.

That's not bad at all. I'm now torn between the ES 16" and the SW 14" for my next plunge a couple of months from now. Out of curiosity, can you lift the entire fully assembled set-up, say, 5 meters distance? Are the poles solidly connected to the top and bottom that you can lift the whole lot without anything snapping apart :) ?

For me, it would be a no-brainer: I can see no advantages to the 14" apart from the price and the fact that shrouds are available for it (if you don't fancy spending a couple of hours making one): unless I am very much mistaken, it's smaller in aperture, but it's heavier and its base is wider.

I have lifted the whole kaboodle (just to see of it was possible) - there are handles on the sides of the rocker box. Out of respect for my ageing and knackered back,  I don't intend to do it again, and I wouldn't have fancied staggering/lurching 5 metres with it.

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I'm basically leaning towards this one...but two things are of concern:

1. set-up time

2. Shroud -- which I'm not sure how to make

3. rigidity

4. not sure how high the eyepiece will be...I'm 5.10 ft.  Have you measured it?

On the plus side, it collapses into a smaller size than the Flextube 14-inch..which means making the Mrs happy if I can pack everything away in a small shed. :) And also, I don't need to buy as many accessories, especially upgrading the rubbish Skywatcher stock focuser.

I'll stick around and see how you get on... :)

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Emad,

I had also seriously considered a 'flat pack' truss dob - home made, mind you. The main issue I had was the setting up time - not just putting the scope together but the collimation. It would be interesting to hear other's opinions about setting up time - whether it is actually worth it because of portability.

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I'm basically leaning towards this one...but two things are of concern:

1. set-up time

2. Shroud -- which I'm not sure how to make

3. rigidity

4. not sure how high the eyepiece will be...I'm 5.10 ft.  Have you measured it?

 Which two of those four are concerns? :grin:

1. See  above: 30 mins from car to observing site, including collimation. It'll probably get quicker when I get used to popping the secondary cage on. Since the secondary collimation is maintained, it's only the primary that needed recollimating - and it's really easy with the "stick".

2. I wrapped a bit of fabric around it, pinned it, trimmed it, sewed it. Made button-holes for the secondary cage knobs, put buttons on that attach to loops of dacron cord (kite bridle line)  hanging from the "spare" spider holes, velcro back and front to "relay" the velcro from the secondary cage to the light shield, shock-cord loops (dacron patch-reinforced attachment points) at the bottom (attach to bolts).

3. Seems fine.

4. See above. I'm also 5'10", my eye is 1.65m above ground when I'm wearing normal shoes. The eyepiece is very slightly lower when tube is vertical.

I think you're not too far from me - you're welcome to come along sometime when I take it into the Forest (next time won't be until the Moon is out of the way).

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 Which two of those four are concerns? :grin:

1. See  above: 30 mins from car to observing site, including collimation. It'll probably get quicker when I get used to popping the secondary cage on. Since the secondary collimation is maintained, it's only the primary that needed recollimating - and it's really easy with the "stick".

2. I wrapped a bit of fabric around it, pinned it, trimmed it, sewed it. Made button-holes for the secondary cage knobs, put buttons on that attach to loops of dacron cord (kite bridle line)  hanging from the "spare" spider holes, velcro back and front to "relay" the velcro from the secondary cage to the light shield, shock-cord loops (dacron patch-reinforced attachment points) at the bottom (attach to bolts).

3. Seems fine.

4. See above. I'm also 5'10", my eye is 1.65m above ground when I'm wearing normal shoes. The eyepiece is very slightly lower when tube is vertical.

I think you're not too far from me - you're welcome to come along sometime when I take it into the Forest (next time won't be until the Moon is out of the way).

Thanks, Steve. Very useful and reassuring info.

If the eyepiece height is that manageable, then it's a pretty good.

In my case, I exclusively observe from my back garden...so perhaps if I end up taking the plunge it'll be permanently assembled and probably living in a booth shed since the base is not that wide.

Thanks for the invitation - but unfortunately I don't drive. Unless you're on a bus route then I'm happy to come and have a look :D

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